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With many choices for hot runner molding temperature control systems available today, how do you know what’s the best selection for you? Let’s explore some things you should consider before purchasing your next system.

Assessing your situation
Your selection of a temperature control system is dependent on your specific mold requirements and the molder’s processes. Consider the number of zones, size of run and other aspects of the molding situation. Have a clear grasp of this information before moving any further.

You’ll want to keep in mind your threshold for reliability and maintenance of the equipment, as well as the amount of training you’re willing to do. Features such as alarms, recipe storage, setpoint control, modularity, etc. are all available based on your level of need.

Considering appropriate features
Minimize downtime by considering features in advance.

Consider if a product’s extra features will really be useful in efficient production of good parts. Some features or equipment alterations such as rewiring a mold’s thermocouples reversed with another zone seem like an immediate solution; however, in the long run, more downtime is caused by the difficulty in servicing the controls.

Looking at costs
Analyze based on cost per production part, rather than overall cost.

For example, if 5 million parts are planned for the life of a particular mold, then it may be prudent to spend less than $0.01 per part (or $50,000) on a Hot Runner Control System. If you can reuse the Hot Runner Control Systems on other molds, then this cost per part will be even lower.

Going with a lower-cost, non-modular system may look good up front, but if such a system were to go down for a few days, you’d quickly lose that price advantage.

Examining controllability
When addressing controllability issues in your hot runner system, the answer typically lies in the system’s mechanics or design, not the control system.

To start, you need a well-designed nozzle with proper thermal response. The design should strive to control to the desired setpoint between 15% to 85% output power.

Small plant line voltage differences can also cause significant shortcomings in proportional–integral–derivative (PID) control response as well. For example, a standard 1,000 watt heater rated at 240 VAC running in a plant with 208 VAC can see a drop of up to 25% in available power just due to the rating difference.

Considering heater dry-out methods
When a heater is first started up, some residual moisture is inherent in the ceramic insulator material of the heater element. This moisture causes the ceramic material to allow a small amount of the 240 VAC voltage to “leak” to the ground. When excessive amounts of moisture are in the heater, this leakage current can cause premature heater failures.

To counter this issue, look for controls that offer dry-out methods of each zone which slows down the heating process. This allows the moisture to escape from the heater in a controlled method to prolong heater life. D-M-E’s proprietary SmartStart® and Patented GFI Dry-out routines have been the industry standards for well over 20 years.

Standardizing with multi-use controllers
Most molders receive molds from multiple sources to run. Unless your company uses only standardized molds, you can’t use one controller for all molds. Variations of mold wattages, zone counts, mold connections, power line voltages, amp draw and other factors won’t allow it.

Some standardization can be done by following SPI communications protocol. Keep in mind, however, that SPI does not have standards for more complex commands, nor does it always translate globally; many in Europe will follow Euromap, etc.

Look to your essential resource
D-M-E Control System products are proof of our continuing tradition of providing robust, reliable and cost-effective solutions to your needs—every step of the way.

Reliable D-M-E control systems dating to the mid-1970s are still running in the field today. And we continue to provide calibration services and support for those products. That’s a level of dedication that’s unheard of in the industry today.